1. Example 4 Using an Irrational Number in Real Life WAVES For large ocean waves, the wind speed s (in knots) and the height h (in feet) of the waves are related by the model. If the waves are about 9.5 feet tall, what is the wind speed? ( 1 knot is equivalent to about 1.15 miles per hour.) 0.019 h = s h = s SOLUTION Write given model.

2. Example 4 Comparing Real Numbers 0.019 9.5 = Substitute 9.5 for h. = Divide. 500 ≈ Approximate square root. 22.4 ANSWER The wind speed is about 22 knots.

3. Guided Practice In Example 4, suppose the waves grow to about 15 feet tall. What is the wind speed rounded to the nearest knot? for Example 4 ANSWER 28 knots 13.WHAT IF?